JAVEA U3A BACKGAMMON GROUP NOTES - PART TWO STRATEGY

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1 JAVEA U3A BACKGAMMON GROUP NOTES - PART TWO STRATEGY The joy of Backgammon is that you may try to develop a strategy but each time the dice are thrown everything changes so in talking strategy we are perhaps more talking of tactics that will change across the game. Careful timing and attention to the probabilities are the vital tools to succeed at backgammon. One goal is of course to build points in your home board so that when you hit an opponent s blot it is more difficult for them to restart. You should also look to build primes of 4, 5 or 6 points in a row that you control to make it difficult for your opponent to leap over you. But often to build your own points and particularly to skillfully construct a prime you often have to leave a blot in the hope that you can build a point at your next go. If you are adopting this approach then place your blot where it can help to build a prime, and in your home board build your points in turn from the rear as Black this means then 6 then 5 then 4 Yet, at the same time, you must not let your back counters get trapped by your opponent by their building of their home board points. Some strategies propose that you split these two back counters early for ease of escape, others prefer to wait on the 6,5 throw or the doublet that can get them out more safely. It s all about timing of course. A point held back in your opponent s home board is often called an anchor. It provides a safe-harbour for any counters you need to get back from the Bar. In a Back Game players establish a number of anchors (preferably adjacent too) within the opponent s home board to make it difficult for the opponent to get all of their counters safely in to the home board in preparation for bearing off. A back game however is seldom ever initially intended as a strategy, it s more a needs-must response to early setbacks. But make sure you try a few back games to see what the opportunities and potential pitfalls can be. One of the errors a beginner often makes is to skip out of the opponent s home board early. Often it is better to stay to be a nuisance to their plans to build points and bear off. It s often tempting to move all of your middle counters (that start on point 13) up to build a prime in the outer board and/or points in your home board. But it is usually wise to leave a point blocked here too to provide a communication link between your forward and back counters. Beginners tend to play safe and use their throws to keep their counters safely on their own points, often building points with many counters on the one point, some call these candlesticks or monoliths. They soon learn that you need to speculate to accumulate and that you need to take the risk of leaving blots as builders or bridges to expand and gain new points you. There is no point in having more than two counters on a point, with the exception of them having a spare counter to act as a builder.

2 Again many beginners adopt the strategy both of exposing blots and hitting opponent s blots far too readily. With experience they start to become more guarded about when and where to leave a blot and particularly when it is advantageous to hit a blot and when to leave it alone. Hitting a blot in your opponent s home board is clearly advantageous because it is sent back by 19 to 24 points, whereas one in your home board is hardly disadvantaged by being removed to the bar (unless you have many of the points blocked of course). One worthwhile strategy is to aim to build what are called Primes where you control adjacent points to make it harder for the opponent to safely cross your area. A Full Prime is where you have a set of six consecutive points so that it is impossible to vault across your prime. In some games you may choose to sprint (with the benefit of the right sort of throws) and skip over the opponent while they wearily are trying to build their prime. Others use their throws to try to trap the opponent s back counters behind a powerful prime. When you start to play the trick is to try them all out, see which ones work in which situations and which you are most comfortable adopting. Your decisions may also be different based upon where you are in the game or in the series of games against this opponent. If you are ahead then there s no need to take unnecessary risks. If you have decided to run for home, or are hastening there to try and avoid a gammon (or backgammon) then it is vital to cross corners. Because the four quadrants on the board are each six points they are a direct analogue of the die with its six numbers. You should therefore maximize each throw so that if for example you (playing Black) had pieces on points 7, 9 and 11 and throw a 5,1 you must move the counter on 11 through to the next quadrant using the 5, and the one on 7 also through to 6. Both of these counters are now theoretically one die face away from being borne off. ETIQUETTE RULE NINE: in a situation where both players are bearing off the normal stricture of not throwing before the other has picked up their dice is relaxed. So that you can throw your dice, still into your right hand board before the opponent has collected their last throw, but clearly not before they ve moved it! When you are moving to the phase of bearing off your opponent is often still present in your home board and so there is a defensive technique you should adopt. Make sure the rearmost points that you are holding stay even. This is so that if you throw two high numbers or a double you do not have to leave a blot for your opponent. It is also sensible not to rush to bear off but instead use your throws to creep over your opponent safely.

3 OPENING MOVES Rather like chess there are clear opening strategies and you need to establish the right move for each of the various potential opening throws. Since the huge increase in computer-based and on-line games every possibility has been explored and the most helpful are generally known to most players as shown below. Though there are 36 ways in which the dice can actually fall, of course several are effectively the mirror image of each other, so there are in fact only 21 outcomes: 6,6 6,5 6,4 6,3 6,2 6,1 5,5 5,4 5,3 5,2 5,1 4,4 4,3 4,2 4,1 3,3 3,2 3,1 2,2, 2,1 1,1 A little preliminary strategy needs to be considered. There are two points that prove extremely powerful and are worthy of your attention early in the game. The first is the bar point this is point 7 (playing Black and point 18 playing White). Clearly these block a throw of six from the two opponents counters (on points 1 and 24) and so are worth blocking as soon as you can. The second is your Five point, some call it the golden point that s point 5 (for Black, 20 for White). This too is useful to block off as early in the game as you can. Six of the possible 21 opening outcomes (28.6% of them) enable you to build one of these two points straight away (each here explained as if you are playing Black): - 1,1 of course gives you four ones and you could use two of these from the 8 point to build the bar point. As two from the 6 point would leave a blot on 6, you would normally use the other 1s elsewhere perhaps move your two back counters from 24 to ,3 you should move a counter from each of 8 and 6 to build the five point - 1,6 you should move a counter from each of 8 and 13 to build the bar point - 3,3 allows two from the eight point to build the five point or two from the 13 point to run through and build the bar point, though you may prefer to split the four 3s to - 4,4 allows you to run two counters through from the 13 point to build the five point. - 5,5 allows you to run two counters right through from 13 to build your three point. Note: it s not just about building your own, deny your opponent s own Bar and Five Points whenever possible too! Another early strategy should be to try to build points in your home board, such that if you should hit your opponent s blot then it is difficult for them to re-enter readily. So a further six of the possible opening throws (including the residue of one from above) could be used to do this: - 2,2 allows two from the six point to build the four point - 2,4 allows you to build the 4 point from 6 and 8

4 - 3,3 two 3s were used above to build the five point, and you could use the other two 3s to move from the six point and build the three point - 3,5 allows you to build the 3 point from 6 and 8-4,4 you could use two of the 4s from the 8 or the 6 point to build at 4 or 2, though in the latter case many believe that building the 2 point this early carries your counters too far out of the active game - 6,4 you could use one from the 8 point and one from 5 to build the 2 point, but see under 4,4 that some believe this to be going too far Other opening outcomes that are promising are: - 6,6 here you can use two 6s to move your two counters on 24 to build point 18, denying your opponent their bar point and the other two 6s can move from 13 to 7 to build your own bar point. - 6,5 run one of your rear counters from 24 through to 13, it gets it safely to one of your points and the blot is so deep into opponents home board that it should prove to be no problem and it would only be going back one point by being hit! Somewhat more confusing are what to do with the following: - 5,5 though a pleasant doublet it s not that great for an opening throw - 6,4 was mentioned above as a possible use of counters from 8 and 6 to build the 2 point, the other options are to run one of your rear counters from 24 through to 14. Or you can move a rear counter from 24 to 18 (trying to build opponents bar point) and use the 4 from 13 to the 9 point as a builder later for bar, five or a home board point. 6,3 two options here move a rear counter through to the 15 point. Or, one of the rear counters to opponents bar point and the 3 used from 13 to 10 as a builder. 6,2 similar two options here a back counter through to 16 or one back counter to the opponent s bar point and the 2 from 13 to 11 as a builder. 5,4 either a back counter from 24 to 20 and another moves from 13 to safety on 8. Or, if you need to play some catch up then move two counters from 13 one to 9 and one to 8. 5,2 either a back counter from 24 to 22 and another moves from 13 to safety on 8. Or, two counters move from 13 one to 11 and one to 8. 5,1 either a back counter from 24 to 23 and another moves from 13 to safety on 8. Or, one counters move from 13 to 8 and gamble with one from 6 to 5 to try to build your five point, or if you don t need to take the risk then slide a back counter from 24 to 23

5 Now we come to the not so simple or pleasant ones in that you probably have to create two blots: 4,3 most players move the 3 with a back counter from 24 to 21 and a middle counter from 13 to 9, but of course there are many other options none of them particularly helpful 4,1 beginners will tend to run a counter from 13 to 8 keeping things tidy, bt you should usually move a back counter from 24 to 23 and a middle counter from 13 to 9, or, of course, the 1 could be used speculatively as a builder on your 5 point or even your bar point 3,2 again forsaking the beginners 13 to 8 tidy move, you should use the three on a back counter 24 to 21 and a middle one for the 2 from 13 to 11 2,1 is a pretty dire throw at most stages of the game, current wisdom says to move a rear counter the 2 from 24 to 22 and put a builder on your five point 6 to 5.

6 PROBABILITIES In a game you will often need to achieve a particular single number with your two dice, and sadly in some cases you need both dice to fall favourably. So it is invaluable to know what your odds are of getting that particular throw. Let s just illustrate why this is so important. Each die you use has six sides, six possible outcomes. In backgammon we use two dice and these have 36 possible outcomes, that can be shown thus: 1,1 2,1 3,1 4,1 5,1 6,1 1,2 2,2 3,2 4,2 5,2 6,2 1,3 2,3 3,3 4,3 5,3 6,3 1,4 2,4 3,4 4,4 5,4 6,4 1,5 2,5 3,5 4,5 5,5 6,5 1,6 2,6 3,6 4,6 5,6 6,6 So for example if you need a 6,6 then with the first die you have just a one in six chance of getting that required 6. Exactly the same probabilities exist for the second die. So there is only one favorable outcome, or only a 1 in 36 chance that you will get both 6s that is a 35-to-1 shot. If you need two different numbers, say 3 and 4, then the odds are different because there are now two favourable outcomes from among the 36, the odds are therefore 2 in 36 which is approx 17-to-1 against. So this is almost twice as likely as getting the 6,6. What if you find yourself 7 points away from an opponent s blot, what are the odds of hitting it? You can achieve this with a 6,1 or 1,6, a 3,4 or 4,3, a 5,2 or a 2,5 so you have six out of the 36 throws that will be favourable, a 5-to-1 shot, that s three times more likely than getting that 3 and 4 and seven times more likely than the 6,6. Let s assume you need a 1, then this has eleven favourable outcomes 1,1 1,2 1,3 1,4 1,5 1,6 2,1 3,1 4,1 5,1 or 6,1 So 11 chances in 36 that s almost a 3-to-1 shot. You need to hit 6 any way it comes, here you have 15 favourable outcomes, 15 chances in 36, this is starting to work up to around a 2-to-1 shot well it s 42% likely!

7 Odds of re-entering from the bar. To get your single counter off the bar and back into the game is often a vital issue. This chart shows your chances: Number of Blocked Points Odds for possible re-entry 0 36/ / / / / /36 6 0/36 Bearing off. You have a counter on each of the points 6, 4 and 2, your opponent has three left too and they are all on their 1 point. You throw a 6 and a 1 so happily bear off the counter from the 6 point, but what to do with the 1? Does it matter? Well not if your opponent throws a double, but yes if you look at the odds. - you could move the one at the 2 point to 1 and leave yourself with a 4 and a 1 to get. There are in fact 29 favourable outcomes for you to bear these two off. - If you instead moved the 4 point to leave yourself with a 3 and a 2 there are only 25 favourable outcomes for you to bear them off. So there s a 16% better chance to win from 4,1 than 3,2. Odds of hitting a particular number: Hitting 1 has 11 successful outcomes all directly bearing a % Hitting 2 has 11 direct outcomes and a further one that is indirect (1,1) 33.33% Hitting 3 has 11 direct outcomes and 3 indirect (1,2 2,1 1,1) 38.9% Hitting 4 has 11 direct outcomes and 4 indirect 41.7% Hitting 5 has 11 direct outcomes and 4 indirect 41.7% Hitting 6 has 11 direct outcomes and 6 indirect 47.2% So your chances keep getting better from one to six, so that at six points away from somewhere you have the highest (47%) likelihood of hitting it, but look what happens once you are farther away. Moving from 6 to 7 (or 8) and your chances shrink threefold!, Move from 6 to 10 away and your chances have shrunk eight times! Hitting 7 or 8 has six favourable outcomes 16.7% Hitting 9 has only five favourable outcomes 13.9% Hitting 10 or 12 has just three favourable outcomes 8.3% Hitting 11 has just two favourable outcomes 5.5 % Hitting 15, 16, 18, 20 or 24 each have just the one favourable outcome 2.8% Of course 13, 14, 17, 19, 21, 22 and 23 cannot be achieved with two dice, but

8 Odds of getting one or two counters off the bar: Open Points 1 piece 2 pieces 1 31% 3% 2 55% 11% 3 75% 25% 4 89% 44% 5 97% 69% 6 100% 100% Just look at the numbers against the one open point with one counter on the bar you still have an almost 1-in-3 chance of getting in, have that second blot hit onto the bar and your chances are reduced tenfold!